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    1   /* Generated By:JavaCC: Do not edit this line. CharStream.java Version 4.1 */
    2   /* JavaCCOptions:STATIC=true */
    3   package net.sourceforge.pmd.lang.ast;
    4
    5   /**
    6    * This interface describes a character stream that maintains line and
    7    * column number positions of the characters.  It also has the capability
    8    * to backup the stream to some extent.  An implementation of this
    9    * interface is used in the TokenManager implementation generated by
    10   * JavaCCParser.
    11   *
    12   * All the methods except backup can be implemented in any fashion. backup
    13   * needs to be implemented correctly for the correct operation of the lexer.
    14   * Rest of the methods are all used to get information like line number,
    15   * column number and the String that constitutes a token and are not used
    16   * by the lexer. Hence their implementation won't affect the generated lexer's
    17   * operation.
    18   */
    19
    20  public interface CharStream {
    21
    22    /**
    23     * Returns the next character from the selected input.  The method
    24     * of selecting the input is the responsibility of the class
    25     * implementing this interface.  Can throw any java.io.IOException.
    26     */
    27    char readChar() throws java.io.IOException;
    28
    29    /**
    30     * Returns the column position of the character last read.
    31     * @deprecated
    32     * @see #getEndColumn
    33     */
    34    int getColumn();
    35
    36    /**
    37     * Returns the line number of the character last read.
    38     * @deprecated
    39     * @see #getEndLine
    40     */
    41    int getLine();
    42
    43    /**
    44     * Returns the column number of the last character for current token (being
    45     * matched after the last call to BeginTOken).
    46     */
    47    int getEndColumn();
    48
    49    /**
    50     * Returns the line number of the last character for current token (being
    51     * matched after the last call to BeginTOken).
    52     */
    53    int getEndLine();
    54
    55    /**
    56     * Returns the column number of the first character for current token (being
    57     * matched after the last call to BeginTOken).
    58     */
    59    int getBeginColumn();
    60
    61    /**
    62     * Returns the line number of the first character for current token (being
    63     * matched after the last call to BeginTOken).
    64     */
    65    int getBeginLine();
    66
    67    /**
    68     * Backs up the input stream by amount steps. Lexer calls this method if it
    69     * had already read some characters, but could not use them to match a
    70     * (longer) token. So, they will be used again as the prefix of the next
    71     * token and it is the implemetation's responsibility to do this right.
    72     */
    73    void backup(int amount);
    74
    75    /**
    76     * Returns the next character that marks the beginning of the next token.
    77     * All characters must remain in the buffer between two successive calls
    78     * to this method to implement backup correctly.
    79     */
    80    char BeginToken() throws java.io.IOException;
    81
    82    /**
    83     * Returns a string made up of characters from the marked token beginning
    84     * to the current buffer position. Implementations have the choice of returning
    85     * anything that they want to. For example, for efficiency, one might decide
    86     * to just return null, which is a valid implementation.
    87     */
    88    String GetImage();
    89
    90    /**
    91     * Returns an array of characters that make up the suffix of length 'len' for
    92     * the currently matched token. This is used to build up the matched string
    93     * for use in actions in the case of MORE. A simple and inefficient
    94     * implementation of this is as follows :
    95     *
    96     *   {
    97     *      String t = GetImage();
    98     *      return t.substring(t.length() - len, t.length()).toCharArray();
    99     *   }
    100    */
    101   char[] GetSuffix(int len);
    102
    103   /**
    104    * The lexer calls this function to indicate that it is done with the stream
    105    * and hence implementations can free any resources held by this class.
    106    * Again, the body of this function can be just empty and it will not
    107    * affect the lexer's operation.
    108    */
    109   void Done();
    110
    111 }
    112 /* JavaCC - OriginalChecksum=0c387fa4d138cb757cb48b36d8bfec55 (do not edit this line) */